Somewhat similar to the confirmation bias is the ingroup bias, a manifestation of our innate tribalistic tendencies. And strangely, much of this effect may have to do with oxytocin — the so-called "love molecule." This neurotransmitter, while helping us to forge tighter bonds with people in our ingroup, performs the exact opposite function for those on the outside — it makes us suspicious, fearful, and even disdainful of others. Ultimately, the ingroup bias causes us to overestimate the abilities and value of our immediate group at the expense of people we don't really know.
Though we're often unconscious of it, we love to go with the flow of the crowd. When the masses start to pick a winner or a favorite, that's when our individualized brains start to shut down and enter into a kind of "groupthink" or hivemind mentality. But it doesn't have to be a large crowd or the whims of an entire nation; it can include small groups, like a family or even a small group of office co-workers. The bandwagon effect is what often causes behaviors, social norms, and memes to propagate among groups of individuals — regardless of the evidence or motives in support. This is why opinion polls are often maligned, as they can steer the perspectives of individuals accordingly. Much of this bias has to do with our built-in desire to fit in and conform, as famously demonstrated by the Asch Conformity Experiments.
Projection BiasAs individuals trapped inside our own minds 24/7, it's often difficult for us to project outside the bounds of our own consciousness and preferences. We tend to assume that most people think just like us — though there may be no justification for it. This cognitive shortcoming often leads to a related effect known as the false consensus bias where we tend to believe that people not only think like us, but that they also agree with us. It's a bias where we overestimate how typical and normal we are, and assume that a consensus exists on matters when there may be none. Moreover, it can also create the effect where the members of a radical or fringe group assume that more people on the outside agree with them than is the case. Or the exaggerated confidence one has when predicting the winner of an election or sports match.
People tend to pay more attention to bad news — and it's not just because we're morbid. Social scientists theorize that it's on account of our selective attention and that, given the choice, we perceive negative news as being more important or profound. We also tend to give more credibility to bad news, perhaps because we're suspicious (or bored) of proclamations to the contrary. More evolutionarily, heeding bad news may be more adaptive than ignoring good news (e.g. "saber tooth tigers suck" vs. "this berry tastes good"). Today, we run the risk of dwelling on negativity at the expense of genuinely good news. Steven Pinker, in his book The Better Angels of Our Nature: Why Violence Has Declined, argues that crime, violence, war, and other injustices are steadily declining, yet most people would argue that things are getting worse — what is a perfect example of the negativity bias at work.